Selective printing machine employing magnetic fields



Feb. 27, 1968 R. MULLER 7 3,370,545

SELECTIVE PRINTING MACHINE EMPLOYING MAGNETIC FIELDS Filed May 26, 1965'7 Sheets-Sheet l INVENTOR.

RUDOLF MULLER Feb. 27, 1968 R, MULLER 3,370,546

SELECTIVE PRINTING MACHINE EMPLOYING MAGNETIC FIELDS Filed May 26, 19657 Sheets-Sheet 2 45 32d 32e 32f a 7 36 78 36b 38c 78c IN V EN TOR.

' RUDOLF MULLER BY R. MULLER Feb. 27, 1968 SELECTIVE PRINTING MACHINEEMPLOYING MAGNETIC FIELDS 7 Sheets-Sheet 5 Filed May 26, 1965 INVENTOR.

RUDOLF MULLER Feb. 27, 1968 R. MULLER 3,370,546

SELECTIVE PRINTING MACHINE EMFLOYING MAGNETIC FIELDS Filed May 26, 1965'7 Sheets-Sheet 4 a v F/g.3a I

INVENTOR.

RUDOLF MULLER BY Feb. 27,1968 R. MULLER 3,370,546

SELECTIVE PRINTING MACHINE EMPLOYING MAGNETIC FIELDS I Filed May 26,1965 7 Sheets-Sheet 5 96 22/ Q 5 7/ r2 r3 2 lzoa 19% T 20c -21 9/ 2 i79c IN V EN TOR.

RUDOLF MULLER BY R. MULLER Feb. 27, 1968 SELECTIVE PRINTING MACHINEEMPLOYING MAGNETIC FIELDS Filed May 26, 1965 7 Sheets-Sheet 6 INVENTOR.

RUDOLF MULLER R. MULLER Feb. 27, 1968 SELECTIVE PRINTING MACHINE. E

MPLOYING MAGNETIC FIELDS Filed May 26, 1965 Y 7 Sheets-Sheet 7 INVENTOR.

RUDOLF MULLER United States Patent 3 370,546 SELECTIVE PRINTIN G MACHINEEMPLOYING MAGNETIC FIELDS Rudolf Muller, Grunwald, near Munich, Germany,assignor to Agfa Aktieugeseilschaft, Leverkusen, German y Filed May 26,1965, Ser. No. 458,928 Claims priority, appiication Germany, June 5,1964, A 4,229 24 Claims. (Cl. 10191) ABSTRACT OF THE DISCLOSURE Selectedtext sections formed of magnetizable ink on a first surface aretransferred by the magnetic fields of electromagnets to a secondsurface, while non-selected text sections remain on the first surface sothat copy sheets having different selected text sections can be producedfrom the one printing form having all text sections.

The present invention relates to a selective printing machine, and to amethod of selective printing, and more particularly to an apparatus andmethod for printing only selected sections of a printing form which isinked with a magnetic ink.

Known printing machines for printing selected sections of a printingform use pressure rollers which are moved between a printing positionfor printing a selected section, and an inoperative position foromitting an undesired section. Due to the substantial masses involved inrapidly shifting the pressure roller, the speed of the machine islimited, and the operation is comparatively noisy.

It is one object of the invention to overcome this disadvantage of knownmachines for printing selected sections of a text, and to provide aselective printing machine in which only ink is transferred fromselected sections of a first surface to corresponding sections of asecond surface by a magnetic field.

Another object of the invention is toprovide a selective printingmachine in which no heavy masses are moved, and which operates at highspeed without producing 'a substantial noise.

Another object of the invention is to provide a selective printingmachine in which the imprints of selected text sections which are spacedon the printing form, appear in adjacent positions on the surface towhich they are transferred.

Another object of the invention is to provide a selective printingmachine in which a first surface inked with magnetic ink moves insynchronism with a second surface to which the ink is transferred by amagnetic field, while both surfaces are stopped while the magnetic fieldis actually effective to transfer the ink.

The magnetic ink which is used in the printing machine and in the methodof the present invention, is known, and not an object of the presentinvention. The ink contains the conventional materials of an offsetprinting ink and contains between 50 and 70% by weight highly permeablemagnetic pigment particles. In accordance with one method of theinvention, a magnetic field is produced in a limited area, a magneticink is applied to a first surface, and the first surface and a secondsurface forming a gap with the first surface are moved through themagnetic field which may be produced by direct current or by analternating current so that the magnetic ink is transferred by themagnetic force from a limited area of the first surface to acorresponding area of the second surface. In one embodiment of theinvention, the magnetic ink is transferred from an inking roller only toselective sections of the printing form. In another embodiment of theinvention the magnetic ink is transferred 3,376,546 Patented Feb. 27,1968 from selected sections of the printing form to a copy. In anotherembodiment, the magnetic ink is transferred from selected sections ofthe printing form to the blanket of an offset cylinder, and in anotherembodiment of the invention the magnetic ink is transferred fromselected sections of the surface of the blanket of an offset roller to acopy sheet.

In the arrangement of the present invention, no mechanical parts areaccelerated, and only the magnetic ink is moved. The starting andstopping of selective printing operations can be consequently carriedout at extremely high operational speeds, and the printing cylinder-canrotate at a speed equal to the speed of continuously operating printingmachines, whereas conventional selective printing machines require a farlower speed of the printing roller carrying the printing form.

The method of the present invention can be applied to any known printingprocess. Particularly, electro-photographic and similar printing formsmay be used, which produce an adhesive force varying on different imageportions and acting on a die powder containing magnetizable particles. iI

In a preferred embodiment of the invention, the ink image is transferredto the rubber blanket of an offset roller, or a magnetic printing formis used. It is advantageous to moisten the printing form so that theelectromagnetic means producing the magnetic field can be small whilethe film of moisture permits a close approach of the surfaces betweenwhich the ink in transferred without transfer of magnetic ink byadhesion while the electromagnetic means is not energized.

Magnetic printing foils, standard ofiset foils, or plain carrier sheetsmay be used. Magnetic printing foils consist of a carrier coated with alayer consisting of a permanently magnetic material and a substanceforming a film. The text is produced either by a magnetic stylus, or byirradiation with ultra-red light using the Currie point of the magneticlayer. A standard offset foil is produced in a conventional manner by atypewriter, or by an optical process. Plain carrier sheets receive atext consisting of a highly magnetically permeable, temporarilymagnetizalbled ink or die which is manually or by typewriter appieAccording to the preferred embodiment of the inventron, a printing foilwhich carries a magnetic image of the text is inked from a spaced inkingroller without touching the same by the magnetic field produced by themagnetic image, while the transfer of the magnetic 111k to a foil havinga text consisting of a highly permeable, tightly adhering substance, iscarried out without engagement of the surfaces by means of a magneticfield produced by an electromagnetic means.

The energization of the electromagnetic means and the control of themagnetic field is obtained by control and selector mean which permit theselection of sections, such as lines or columns, of the text forprinting or transfer. A selector key is associated with each section ofthe text. In a preferred embodiment of the invention, several sets ofkeys are provided, each set of keys being associated with a column, andthe keys of each set respectively associated with lines so that by eachkey, the part of a line corresponding to a column is controlled.

It will be understood that the term line and column are usedinterchangeably, and that sets of selector keys can be respectivelyassociated with lines, while each selector key of the set is associatedwith a column. Selective printing operations of this type have theadvantage that invoices can be reproduced with prices and discounts forwholesale dealers, without discounts for retail customers, withoutprices as delivery notice, and without prices and addresses as warehousereceipts.

The selector means of the machine of the present invention may becontrolled by mechanical or electronic program storing devices whichstore all possible selections, and the number of desired prints for eachselection, and then automatically control the machine to print differentcombinations of text sections in succession while producing for eachcombination of text sections the desired number of copies.

In accordance with one embodiment of the invention, the control signalsof the selector means simultaneously control the advance of the copysheet. Consequently, the copy sheet is only transported while a selectedsection of the text is printed thereon, whereas it is at a standstillwhen undesired sections of the text pass the printing area. As a result,the imprints of the selected sections appear adjacent each other on thecopy sheet, although they are spaced on the printing form. For example,the head sec tion of the text, and the few selected lines of workspecifications can be printed on a small slip for use as warehousevouchers, work operations control cards, piecework job cards and similarpurposes.

The term magnetic ink is used in this application to describe an inkwhich will be attracted or repelled by a magnetic force when located ina magnetic field.

The magnetic printing ink used in the machine of the present inventioncontains the highest possible proportion of magnetic pigment which isbound with a binder material similar to an offset oil which is quicklyabsorbed by the copy sheet on which the image of the text is to beformed by magnetic transfer and without contact of the ink carryingsurface and the imprint receiving surface. The transferred ink will bedrawn into the paper of the copy sheet together with the bindermaterial.

The greatest forces act on the magnetic ink when highly permeablemagnetic substances are contained in the ink. In order to avoiddisturbances of the operation by undesired premagnetization of the ink,its coercive force should be low. However, under certain circumstancesit may be advantageous to use pigments which have an average coerciveforce and residual magnetism. In an alternating magnetic field, themagnetism of these particles is continuously reversed, but the particlesretain a substantial residual part of the first magnetization.Consequently, the pigment particles carry out an oscillating movement inthe alternating magnetic field which reduces the viscosity of the inkand facilitates transfer by the magnetic field.

A selective printing machine according to one embodiment of theinvention comprises electromagnetic means for producing a magnetic fieldwhich has a predetermined Width corresponding to a section of a text.Means are provided which have first and second surfaces forming a gap.For example, the surface of the blanket of an offset roller forms a gapwith the copy sheet, or an inking roller forms a gap with the surface ofthe printing form, or the surface of the printing form on a printingcylinder forms a gap with the surface of the blanket of an offsetcylinder. Drive means move the first and second surfaces in synchronismthrough the magnetic field of the electromagnetic means. Selector meanscontrol the energization of the electromagnetic means, and preferablyinclude selector keys and selector switches and a rotary contact whichrotates in synchronism with the movement of the surfaces.

Moistening means are advantageously provided for moistening the printingform before ink is transferred to the same. In accordance with theinvention, the core of the electromagnetic means has a narrow elongatedend face of a shape corresponding to the shape of a line of the printingform. Preferably, the core is subdivided into core sections, each ofwhich has a rectangular end face whose shape corresponds to the shape ofa line section within a column of the printing form.

In one embodiment of the invention, the printing form is inked,preferably only at selected text sections, and transfers the inked textin the form of a mirror image to the blanket of an offset roller. Theinked image of the offset roller is then transferred to the surface of acopy sheet by the magnetic field of an electromagnetic means which isenergized only when a selected section of the text on the offset blanketpasses the printing area and the electromagnetic means.

In one embodiment of the invention, the printing formv has an innerelastic layer covered by a magnetizable foil. When the printing rollerand the offset roller are spaced by a small air gap or hardly touch eachother, the magnetic force deforms the printing form so that an actualengagement under pressure takes place between the printing form and theoffset blanket which improves the transfer of ink under the action ofthe magnetic field. Such a deformable printing form permits the transferof ink even if the same is very little magnetic, or even nonmagnetic.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompariying drawings, inwhich:

FIG. 1 is a fragmentary cross sectional view illustrating one embodimentof the invention;

FIG. 2 is a' fragmentary axial view illustrating a detail of FIG. 1 onan enlarged scale, and including an electric diagram;

FIG. 3 is a fragmentary cross sectional View illustrating a secondembodiment of the invention;

FIG. 3a is a diagram of a modified electric circuit of the embodiment ofFIG. 3;

FIG. 4 is a fragmentary cross sectional view illustrating an inkingarrangement according to the invention;

FIG. 5 is a fragmentary cross sectional view illustrat ing amodification of the embodiment of FIG. 1, the selector circuit beingomitted for the sake of simplicity;.

FIG. 6 is a fragmentary cross sectional view illustrat ing anotherembodiment of the invention, the selector circuit being omitted for thesake of simplicity; and

FIG. 7 is a cross sectional view illustrating another embodiment partsof which correspond to the construction of FIGS. 1 and 2 and providedwith means for stopping the movable parts during the transfer of ink.

Referring now to the drawings, and more particularly to FIGS. 1 and 2which illustrate a first embodiment of the invention, a printing roller1 is mounted on a shaft 1a and carries on its peripheral surface aprinting form in the form of a thin printing foil which is clamped tothe surface of printing roller 1 by a clamping device 2. The printingform may carry a text divided into sections, for example line sectionsand column sections. The printing form may be attached to the printingroller in such a position that the line sections extend in axialdirection, and the column sections extend in circumferential directionof the printing roller.

An inking roll 4 is in rolling engagement with the surfaceof printingform 3, and receives a magnetic ink from a container 6 by means of adoctor roll 5, and a transfer roll 7 which is operated between aposition engaging the surface of doctor roll 5 and a position engagingthe surface of inking roll 4. Doctor roll 5 may be operated to turn inan intermittent movement.

A moistening roll 8 is partly immersed into a moistening liquid in acontainer 9 and cooperates with inking roller 4 to apply a moisteningliquid in the form of a thin film onto the layer of magnetic ink onroll4.

This inking arrangement is known, and not an object of the invention.However, in accordance with the present invention, a magnetic ink isused.

An' offset roller 10 is mounted on a shaft 10a, and carries on itsperipheral surface, a rubber blanket 12 which is held by a clampingdevice 11. Rollers 1 and 10 are connected to each other for synchronousrotation by a pair of meshing gears, not shown, and a pulley 13 is fixedto roller and connected by a belt or chain to another pulley 15 which issecured to a control shaft 40.

A supporting table 30 is located below roller 10, and adapted to supportcopy sheets 192 transported by pairs of transporting rollers 26, 27 and28, 29. A stack 24 of copy sheets rests on a support 23 which has aninclined guide face leading to transporting rollers 26, 27. An automaticsheet feeding device, not shown, includes a feeding roller 25 resting onthe top sheet of the stack and performing a reciprocating motion. Duringmove? ment toward transporting rollers 26,27, roller 25 is blocked sothat a sheet is transported, and during the return stroke, roller 25turns so that the respective upperm'ost sheet is not displaced. Aone-Way clutch, not shown, is provided for this purpose.

A box 31 is provided for receiving printed copy sheets after the sameare released by transporting rollers 26, 27, and are transported only bytransporting rollers 28, 29. Transporting rollers 26 to 29 are connectedby a trans.- mission, not shown, with roller 10 so as to be driven insynchronism with the same, and are dimensioned to transport copy sheets16?. at a speed which is the same as the peripheral speed of the blanket12 on roller 19. The surface of table Sit, and thereby the copy sheetthereon, are spaced from the surface of the blanket so that a copy sheettransported by the transporting rollers will not be in contact with thesurface of the blanket 12.

Support table 30 has a slot or cutout 38a in which core parts 320 to 32of a core 32 of an electromagnetic means are located. Each core sectionhas a rectangular surface elongated in axial direction, and narrow incircumferential direction of roller 10, and all core sections 32c to 32fextend in axial direction substantially for the entire axial length ofblanket 12. In circumferential direction of the roller 10, which is alsothe direction in which copy sheet 102 is transported, the core 370 to32d has a predetermined width corresponding to a line section of theprinting form 3 and to a corresponding line section of a copy sheet 102,The axial width of each core section 32c to 32 corresponds to the widthof a column of printing form 3, and to a corresponding column of a copysheet 182.

If a printing form is attached to printing roller 1 in the position inwhich its columns extend in axial direction and its lines extend incircumferential direction, the circumferential width and the axiallength of core sections 320 to 32 must be corresponding designed.However, it is preferred to arrange the narrower line sections in thedirection of the movement of the copy sheet indicated by an arrow inFIG. 1. I I

The core 32c to 32f is connected by a pair of yoke portions 32a, 32b tothe hollow shaft 10a which is secured to stationary frame walls 34.Roller 10 is freely rotatable on shaft 10a, and connected by gears 41,42 with printing roller 1, as best seen in FIG. 2.

The stationary shaft 10a carries a series of core sections 35:; to 35hwhich have axial lengths corresponding to the axial lengths of coresections 320 to 32 and a narrow circumferential extension, which,however, may be slightly greater than the circumferential extension ofcore sections 32c to 32 Windings 33a to 33d respectively surround coresections 320 to 32f, and windings 36a to 36d respectively surround coresections 35e to 35h. Screws 37a to 37d secure annular portions 35a to35d of core sections 35e to 35] to the stationary shaft 1%.

Each winding 33a to 33d has one end connected by a line 38a to 38d tofour lines 18a to 1811', and each winding 36a to 36a has one endconnected by lines 39a, 39b, 39c, 39d to lines 18a to 18d. The otherends of each Winding are connected to a main line 22 which together withthe other main line 21, is connected to a voltage source.

The direction of the flow of current in windings 33a to 33d, and 36a to36d, is selected so that the core sections 320 to 32 are south poles,and coresections 35e to 35h are north poles, the magnetic field closingthrough yoke portions 32a, 32b, shaft 10a, the peripheral wall of thehollow roller 10, blanket 12, and the air gap between a copy sheet Hi2and the outer surface of'blanket 12, which air gap has a thickness a.

The wall of roller 10 and blanket 12 are made of materials which arehighly permeable for the magnetic flux so that a substantiallyhomogeneous magnetic field prevails in the gap between core sections 320to 32 and blanket 12, and through a copy sheet 102 located in the gap.

Lines 18a to 18d are respectively connected to four rotary contact arms16a to 16d which are mounted on control shaft 40 to rotate insynchronisrn with roller 10 and transporting rollers 26, 27. Eachcontact arm is thus correlated with a pair of core sections, forexample, contact arm 16a is correlated with a pair of core sections 32cand 352, and consequently also correlated with a column section of acopy sheet 102.

Each rotary contact arm passes successively over a plurality ofstationary contacts of which only three contacts 17a, 17b, are shown.The number of stationary contacts in each of the four sets correspondsto the number of line sections of the printing form. Each set ofcontacts 17a to 170 is connected by conductors 19a to to a set ofselector switches 20a, 20b, 20c which are controlled by a set of keysT1, T2, T3.

Consequently, four sets of keys T1 to T3 are provided, each set beingcorrelated with a pair of cooperating yoke sections and with acorresponding column section of the printing form and of the copy sheet.The number of keys in each set corresponds to the number of linesections of the printing form and of the copy sheet, only three keysbeing shown for the sake of simplicity.

When the machine is started, and drive shaft 1a r0,- tates printingroller 1 with printing form 3 so that roller 10 is driven by gears 41,42 and transfers its rotary motion through pulleys 13, 15, and belt 14to the four contact arms 16a to 16d, the same successively andsimultaneously engage the correlated stationary contacts of the foursets of contacts 17a to 170. Transporting rollers 26 to 29 rotate, andfeeding means 25 starts to operate.

Water repellent portions of printing foil 3 are inked by inking roller 4in the usual manner, The ink is transferred to the blanket 12 on roller10 as a mirror image, but cannot form an imprint on a copy sheet 102because the blanket and copy sheet are not pressed against each other,and are actually spaced the thickness a of the air gap between the copysheet and blanket 12.

Before the operation was started, selected keys T were depressed, andthe corresponding contacts 20 closed.

Assuming first that each key T2 of all four sets of keys was depressed,all windings will be energized when the four contact arms 16a to 16dengage stationary contacts 17b. The arrangement is such that at thismoment, a line section of the printing form transferred from theprinting form and located on blanket 12, will be located in the gapbetween core sections 320 to 32 and core sections 35c to 3511.

When the four contact arms engage the four stationary contacts 1% andenergize all windings, an electromagnetic field develops in the gap andeffects transfer of the magnetic ink from the respective narrow sectionof blanket 12 to a corresponding line section of copy sheet 102. Thepreceding inked section and the following inked section of blanket 12 isnot printed on copy sheet 102, since the corresponding keys T1, T3 werenot depressed, and the corresponding selector switches 20a to 200 remainopen.

Assuming that the fourth keys would have been depressed, andcorresponding selector switches closed, then ink would be transferredfrom the respective section of blanket 12 to the fourth line section ofthe copy sheet.

In the preceding example, it was assumed that all keys T2 of the foursets of keys were operated so that an entire line of the printing formwas printed on the copy sheet.

Assuming, however, that only keys of one set of keys were selected anddepressed, for example keys connected with stationary contacts 17engaged by contact arm 16:: then only the pair of core sections 35c, 32cwould produce an electromagnetic field since only windings 36a and 33awould have been energized. Consequently, in each selected line section,only one column section would have been printed.

It is evident that by selection and operating of selected and differentkeys T of the four sets of keys, one or several selected column sectionsof one or several selected line sections can be imprinted on the copysheet.

In order to accomplish this result, it is necessary that the magneticfield produced by the electromagnetic means has in the direction ofmovement of copy sheet 102 a predetermined Width corresponding to a textsection, preferably a line section, of the printing form and of thedesired imprint, and in a direction transverse to the direction ofmovement, a length which may correspond to the entire length of a line,or only to the width of a column of the text.

Referring now to the embodiment of the invention illustrated in FIG. 3,a printing cylinder 1 is mounted on a shaft 1a and carries a printingform 3 which is inked by an inking device 4 to 9 as described withreference to FIG. 1. An offset roller 10 has a blanket 12 to which amirror image of the text of the printing form consisting of magnetic inkis transferred. Transporting rollers 26, 27 receive copy sheet blanksfrom a stack 24 when the feeding device is operated to reciprocateroller 25, as described with reference to FIG. 1. The copy sheet 102 isgripped by a gripping means 46 on a magnetizable roller 47 which ismounted on a shaft 48. A stationary cam, not shown, controls grippermeans 46 in a conventional manner to cause gripper means 46 to grip theleading edge of copy sheet 102 at the proper moment, and to release thesame again when the leading edge approaches a transporting roller 51cooperating with a slanted guide plate 50 so that a printed copy sheetis discharged along guide plate 50 and drops onto a support 31. Aneccentric member 49 is secured to magnetizable roller 47 and to shaft48, and reciprocates the feeding device 125 together with roller 25.

At the beginning of rotation of roller 47, a copy sheet 102 istransported into the open gripper means 46 which close to furthertransport the copy sheet until the same is delivered to discharge roller51.

Rollers 1 and 10 are connected by a gear transmission, not shown, forrotation in synchronism. Rollers 10 and 47 are driven by common drivemeans 52 from which also the drive of rollers 1 and 10 is derived. Inthe position illustrated in FIG. 3, rollers 10 and 47 are disconnectedfrom drive means 52.

Drive means 52 includes a friction wheel 52a cooperating with frictionwheels 54 and 56. Friction wheel 54 is connected with roller 47 bypulley and belt means 53, while friction wheel 56 is connected withroller 10 by pulley and belt means 55.

Friction wheel 54 is turnably mounted on a pivot means provided on alever 57 which is mounted on shaft 48 for angular displacement, andfriction wheel 56 is turnably mounted on a pivot means provided on alever 58 which is mounted on shaft 10a for angular displacement. Aspring 61 acts on lever 57 to press brake wheel 54 against a brake block63, and a spring 62 acts on lever 58 to move friction wheel 56 away froma friction block 64 and into engagement with a blocking lever 66 whichis mounted on a pivot means 65 and urged against portion 58a by a spring67. A release lever 68 is mounted on a pivot 69 and biased by a spring70 to abut a fixed stop 71a.

Electromagnetic means 59 and 60 have movable armatures respectivelyarticulated to levers 57 and 58 so that upon energization ofelectromagnetic means 59 lever 57 is turned in counterclockwisedirection to a position in which friction roller 54 no longer engagesbrake block 63 but is coupled with friction wheel 52a of drive means 52so that the roller 47 is rotated by pulley and belt means 53. Whenrelease lever 68 is manually operated, blocking lever 66 releasesengaging portion 58a, as Spring 62 moves friction wheel 56 into couplingengagement with friction wheel 52a so that roller 10 is rotated bypulley and belt means 55. Energization of electromagnetic means 60 willmove lever 55 from this position to a position in which friction wheel56 is braked by brake block 64 while blocking lever 66 snaps underengaging projection, 58a which is facilitated by slanted engaging faceson portion 58a and on blocking lever 66. Roller 10 can only rotate aftermanual operation of release lever 68.

Blanket 12 is separated from copy sheet 102 and from roller 47 by an airgap having the thickness a so that the surface of the copy sheet is notengaged by the surface of the blanket.

Roller 47 has a series of peripheral cores 47 spaced in circumferentialdirection by narrow gaps. Each core section 47 may extend for the entireaxial length of roller 47 corresponding to the length of a line of theprinting form and of the copy sheet, and be surrounded by a singlewinding 47a, or each core 47 may be divided into a plurality of axiallyadjacent core sections, each surrounded by a winding and having an axiallength corresponding to the width of a column, substantially asdescribed with reference to the stationary cores 320 to 32] of theembodiment of FIGS. 1 and 2.

A pulley and belt drive 14, 15 connects roller 10 with four contact arms16a to 16d which are respectively associated with four axial magnet coresections of the cores 47. Each contact arm cooperates with a set ofstationary contacts, of which only one set comprising three contacts17a, 17b, 170 is shown in FIG. 3. Conductors 19a, 19b, 19c connect eachset of stationary contacts 17a, 17b, 170 with selector switches 20a,20b, 20c which are controlled by keys T1, T2, T3. The number of sets ofkeys T1, T2, T3 corresponds to the number of axial core sections ofcores 47', and the number of selector switches and stationary contactscorresponds to the number of lines of the printing form and of the copysheet.

The four windings on the four axial core sections of each core 47" arewound so that alternating cores 47' are energized in opposite directionswhereby north poles and south poles of cores 47' alternately passthrough the printing line.

Each winding 47a is connected by a conductor 72, a slide contact 76, anda contact ring on shaft 48 engaged by slide contact 76 with acorresponding set of selector switches 20a, 20b, 20c and by the same tothe corresponding stationary contacts 17a, 17b, 17c, and also by aconductor 77 to one end of the winding of electromagnetic means 59. Theother ends of windings 47a to 471 are connected to the insulatedperipheral contact sections of a commutator. The contact sections of thecommutator are again divided into four contact parts which arerespectively engaged by four slide contacts which are connected to amain line 22 which, together with main line 21, is connected to a sourceof voltage.

Due to the provision of the commutator, only adjacent cores 47' locatedin the region of the gap between roller 47 and roller 10 with blanket12, are energized and produce a magnetic field with lines of fluxflowing through the gap from core 47 magnetized to be a north pole tothe adjacent core 47 magnetized to be a south pole. In this manner, amagnetic field is produced in the gap and causes transfer of magneticink from blanket 12 to copy sheet 102. If all four sections of twoadjacent cores 47 are magnetized in opposite sense, an entire axiallyextending line will be transferred to the copy sheet, but if only one orseveral pairs of core sections are energized due to correspondingselections of keys from several sets, the transferred text sections willhave an axial extension corresponding to the axial extension of therespective core sections, and parts of lines'located in selected columnswill be printed.

Before printing of a copy sheet takes place, the operator selectscertain sections of the printing form for printing by depressingselected keys T and closing the corresponding selector switches 29. Itwill be understood that either selected switches of each of the foursets of switches, or the same switch in all four sets may be actuated.In the latter case, all four keys T2, for example, are depressed so thatthe entire second line is printed in all four columns.

Electromagnetic means 59 is connected by line 77 not only to lines '72and the four slide contacts 76, but also to the four sets of selectorswitches 20, and to line 87' leading to a first switch contact 83. Thesecond switch contact 84 is connected by a line 88 to one end of winding60. The respective other ends of windings 59 and 60 are connected tomain line 22 to which slide contact 75 is connected.

Keys T and selector switches 20 are again associated with sections ofthe printing form, and corresponding contacts 17 will be engaged by acontact 79 when the respective section on blanket 12 passes through thegap between the blanket and to adjacent cores 47' of roller 47.

A contact 79 is connected by line 81 to a contact cooperating withswitch contact 84, and a second contact 80 is connected by a line 82 toanother contact cooperating with switch contact 83. Switch contacts 83and 84 are operated by a cam follower 85 cooperating with a camprojection 86 of a cam rotating in synchronism with roller 47. Contacts79, 80 are connected by contact arm 16.

During the operation, the entire text of a printing form 3 on roller 1is transferred to blanket 12 in the form of a mirror image. Theoperation is started by operating release lever 68 so that spring 62couples friction wheel 56 with drive wheel 52a. Electromagnetic means 60is not energized when switch contacts 83, S4 interrupt the connection.Electromagnetic means 59 is energized and moves lever 57 to a positionin which friction wheel 54 is coupled with the drive wheel 52:: so thatroller 47 rotates in synchronism with roller whereby the copy sheet ismoved by gripper 46 at the same speed as blanket 12. Whenever a contactarm 16 passes over a contact 17 selected by actuation of the respectivekey and selector switch 20, the respective windings are energized toattract the ink of a section of blanket 12 and to transfer the ink to acorresponding section of copy sheet 102. When contact means 16, 17interrupts the circuit, electromagnetic means 59 is de-energized, thefriction coupling 52a, 54a is interrupted, spring 61 presses frictionwheel 54 against brake block 63, and roller 47 is momentarily stoppedwhile roller 1%) with blanket 12 continues to rotate with those sectionsof the printed text which are not selected for being imprinted on thecopy sheet. When a contact arm 16 again engages a stationary contact 17selected by closing of the respective selector switch 20,electromagnetic means 59 is again energized so that coupling 52a, 54 isagain engaged, roller 47 rotates, and gripper 47 moves the copy sheet atthe same speed as the blanket, while a magnetic field is produced in thegap to transfer another selected section of the text from blanket 12 tocopy sheet 102 where an imprint will appear directly adjacent thepreceding imprint since roller 47 was at a standstill while roller 10and blanket 12 turned from the first selected section to the secondselected section.

When rollers 1 and 10 have performed one complete revolution, contacts79, 80 are connected by contact arm 16. Switch contacts 83, 84 are inthe closed position so that electromagnetic means 60 is energized andmoves lever 86 with friction wheel 56 away from drive wheel 52a so thatfriction wheel 56 is braked by brake block 64 and rolier 10 and printingroller 1 are stopped. At the same time, electromagnetic means 59 isenergized, and

friction wheel 54 is drawn into engagement with drive wheel 52 wherebyroller 47 is rotated. Since feeding device 125 and discharge roller 51are driven from roller 47, the printed copy sheet is transported untilengaged by roller 51 and deposited on support 31. At the same time, anew copy sheet is inserted into the open gripper 46 which closes to holdthe new copy sheet.

At the moment in which a second copy sheet is ready to be printed,follower roller of switch contacts 83, 84 is engaged by cam portion 86which moves in synchronism with roller 47, so that the circuit ofelectromagnetic means 59, 60 is interrupted. Spring 61 pulls frictionwheel 54 against brake block 63 and stops roller 47 untilelectromagnetic means 59 is energized again when a contact 17 is engagedby the contact arm. Movement of lever 58 under the action of spring 62is blocked by blocking lever 66 until release lever 68 is again operatedwhich starts the next operational cycle in which the same selectedsections are printed. However, before the next actuation of releaselever 68, a new series of sections of the printing form can be selectedby clearing selector switches 29, and operation of other keys T.

The diagram of FIG. 3a shows substantially the circuit of the embodimentof FIG. 3, modified by the addition of a relay 138 controllingelectromagnetic means 59 by operating switch 131 in a line 130. Relay133 is energized by a slide contact 134 in line 132 when one of thecircuits 76a to 76d is closed. Since relay 133 responds even if contacts16a, 79 are closed, switch contact 83 can be omitted.

In the embodiment of FIG. 4, a printing roller 92 is mounted on a shaftand carries a magnetic printing form 91 which is in rolling contact witha moistening roll 8 partly immersed into a liquid in a container 9. Amagnetiza'ble roller 93 is mounted on a shaft 96 and has a peripheralsurface defining a gap with printing form 91. Roller 93 serves as aninking roller and is in contact with an amount of magnetic ink 95accumulated between the peripheral surface of roller 93 and anapplicator plate 94 whose position can be adjusted by an adjusting screw101 screwed into the support of applicator plate 94. During rotation ofroller 93, a thin film of ink forms on its peripheral surface. Roller 93is connected by transmission means with printing roller 92 so thatprinting form 91 and the peripheral sunface of roller 93 move at thesame speed. The periphery of roller 93 is formed by cores 9311 which areseparated by gaps 93a, and surrounded by windings 930. The constructionof roller 93 corresponds to the construction of roller 47 of FIG. 3, andthe cores 93b may the divided into axial sections. Assuming that eachcore 93b extends over the entire axial length of roller 93 correspondingto the axial length of printing form 91, the windings 93c of adjacentcores 93b are energized in opposite directions so that adjacent cores93b form north poles and south poles, respectively on the periphery ofroller 93 whereby a magnetic field is formed in a narrow region of thegap substantially in a printing plane passing through the axes of shafts90 and 96.

Shaft 96 of roller 93 is connected by the slide contact and conductor 98with the main line 22 of a source of direct current. The windings 930respectively have one end connected to mass and to shaft 96 and mainline 22, and other ends respectively connected to the contacts of acommutator 99 rotating with roller 93 and in sliding engagement with aslide contact 100 connected by a line 18 to a rotary contact arm 16which rotates in synchronism with printing roller 92, and is connectedto the same by transmission means, not shown, substantially as describedwith reference to FIG. 1. Contact arm 16 successively engages stationarycontacts 17a, 17b, which are associated with circumferentially adjacentaxially extending elongated line sections of printing form 91, onlythree stationary contacts being shown to represent a far greater numberof stationary contacts correlated to line section.

Each stationary contact is connected by conductors 19a, 19b, 190 toselector switches 20a, 20b, 200 which are selectively operated by keysT1, T2, T3. The selector switches are also connected to the second mainline 21 and thereby to the voltage source.

During operation, rollers 93 and 92 are rotated. When a selected sectionof the printing form 91 is located in the printing plane and in the gap,contact arm 16 either engages a contact 17 whose switch 20 is notclosed, or a contact 17 whose switch 20 is closed since the operatordepressed the respective key T to select the respective section of theprinting form for inking.

If the selector switch 20 associated with the respective section of theprinting form located in the printing plane is open, the respectivewindings are not energized, and no magnetic field is produced in thegap.

However, if a selector switch 20 is closed when the correspondingsection of the printing form 91 passes through the printing plane, thenthe circuit of the responsive winding which at this moment approachesthe gap and the printing plane is closed by engagement of contact arm 16with the respective contact 17, so that a magnetic field is produced inthe gap.

During rotation of rollers 92 and 93, the thin film of magnetic ink onthe peripheral surface of roller 93 is attracted by the magneticprinting form 91 and transferred to the same. However, the ink can onlyadhere to those portions of the magnetic printing form 91 which weremade permanently magnetic while the image of the text was produced onprinting form 91. Consequently, the text portions of the printing formare continuously inked. However, when the rotary contact arm 16 engagesa contact 17 whose selector switch 20 was closed by operation of therespective selector key T, the winding 930 of a core 93b approaching theprinting plane is energized so that a magnetic field is produced in thegap. The windings and cores are designed so that the magnetic field isopposed to the field produced by the magnetic printing form 91 andcompensates the same. Consequently, the ink on the peripheral surface ofroller 93 is not attracted to the printing form, and since the same hasa thin film of liquid, no ink at all adheres to the printing form in therespective text section which is narrow in circumferential directioncorresponding to a narrow magnetic field produced by the respectivecores 93b.

Only selected sections of a printing form 91 are inked in this manner,while non-selected sections are not inked. It is evident that theprinting form inked in this manner can be used in conventional printingapparatus for printing on a copy sheet only the selected and inkedsections.

However, a printing apparatus substantially corresponding to theembodiments of FIGS. 1 or 3 may also be used, in which event theprinting form would be attached to printing roller 1, or directly to theperiphery of roller 10, and a corresponding selection is carried out byoperation of the selector keys so that the ink is transferred from theinked sections of the printing form by magnetic attraction across an airgap and onto a copy sheet, whereby a smudging of the copy sheet betweenselected and printed sections is reliably prevented, since no pressurehas to be applied by the printing form on the copy sheet. Also, adeposit of superfluous ink on lines which are not to be printed can bereliably avoided by transferring the ink from selected sections of theprinting form by a magnetic field in accordance with the invention.

In the embodiment of FIG. 5, a printing cylinder 1 carries a printingform 3 which is inked with magnetic ink by a printing device 4 to 9. Aroller rotates in synchronism with printing roller 1 and carries ablanket 12 to which a mirror image of the text of the inked printingform is transferred. Transporting rollers are provided for transportinga copy sheet 102, as described with reference to FIG. 1.

A narrow magnetic field is produced by a horse-show magnet 103 whosenorth and south poles are located directly below a transported copysheet 102 and are closely spaced from each other to form a narrow airgap 103a. Air gap 103a extends over the axial length of the blanket 12and over a narrow section in the direction of movement of the copysheet. The shape of air gap 103a is such that the flux lines passthrough the gap between copy sheet 102 and blanket 12, permeating thelatter which is made of a rubber material which has a high magneticpermeability.

The magnetic field consists of two substantially homogeneous halveswhich causes transfer of ink from a narrow section of the blanketcorresponding to a text section of the printing form to a correspondingsection of the copy sheet 102. Rotary contact means and selectorswitches as described with reference to FIG. 1 are connected to thewinding of electromagnetic means 103, but not shown for the sake ofsimplicity.

In the embodiment of FIG. 6, a printing roller 1 carries a printing form107 inked by an inking device 4 to 9 and spaced by a gap from a roller10 carrying a blanket 12. A stationary electromagnetic means 104 ismounted in the interior of printing roller 1, and a correspondingstationary electromagnetic means 35' is mounted in offset roller 10. Thearrangement corresponds to the construction of electromagnetic means 32and 35 described with reference to FIG. 1, and corresponding rotarycontact means and selector switches are provided, although not shown inFIG. 6. It is evident that cooperating electro magnetic means 35 and 104will produce a magnetic field whenever energized whereby the ink formingthe text on printing form 108 is transferred to the surface of blanket12.

A stack of copy sheets 24 is provided on a support, and the copy sheetsare successively fed by a feeding roller 25 to transporting rollers andto an automatically opening and closing gripper 105 on a roller 106,substantially as described with reference to roller 47 of the embodimentof FIG. 3. Roller 106, however, is not a magnetizable roller and has nomagnetic windings.

Roller 105 serves as a conventional counterpressure roller exertingpressure against the copy sheet and the blanket 12 of offset roller 10.

Printing form 107 which is secured by a clamping means 2, has an innerlayer 10% consisting of an elasticsheet, which may consist of foammaterial. Printing form 107 is made of a magnetizable material, whichmay be a magnetizable metal, or a synthetic plastic material in whichhighly permeable magnetizable particles are embedded.

When electromagnetic means 104 and 35' are energized, a magnetic fieldis produced in the gap between the printing form and the blanket,exerting a magnetic force on the magnetizable foil 107 producing adeformation of the elastic layer 108 and a bulge in the printing form.In the illustrated construction, magnets 35' and 104 have substantiallythe same distance from printing foil 107. In order to draw a portion ofthe printing foil 107 in a direction toward blanket 12 for reducing theair gap a between the blanket and the printing form, the permeability ofthe rubber blanket 12 and of roller 10 should be greater than thepermeability of printing cylinder 1. When the bulge of the printing formis pressed by the magnetic force against the surface of the blanket, animprint is made even if the ink is not magnetic.

A magnetic cleaning device is provided for removing the inked image fromblanket 12 after each revolution of the same so that a new image can betransferred from the printing form 107 in accordance with anotherselection carried out by operation of keys and closing of selectorswitches, as described with reference to FIG. 1.

The cleaning device includes a permanently magnetic roll 128 which isdriven to rotate in synchronism with roller 10 by transmission means,not shown. The periph eral surface of cleaning roller 128 is spaced byan air gap having a thickness b from the surface of blanket 12. The

13 permanent magnet poles of cleaning roller 128 are schematicallyindicated by the letters N and S representing north pole and south pole,respectively. It is preferred to construct cleaning roller 28 of thinmagnetized discs of which alternating discs have north poles and southpoles, respectively. The ink on blanket .12 is attracted by cleaningroller 128, scraped off by a scraper 12-9 and deposited in a container130.

During operation of the printing machine shown in FIG. 6, ink istransferred from selected sections of the printing form 107 wheneverelectromagnetic means 35, 104 are energized in accordance with aselection carried out by the operator as described with reference toFIGQ 1. Only selected text sections appear circumferentially spaced fromeach other on blanket 12, and are imprinted on the copy sheet due to theprinting pressure applied by counter-pressure roller 106. When thesurface of the blanket is cleaned by cleaning roller 128 by magneticattraction of the ink thereon, the next selection is made by theoperator, and other text sections are transferred to the blanket surfaceand then printed on a copy sheet.

Referring now to the embodiment of FIG. 7, a printing cylinder 1carrying a printing form with axially extending elongated line sectionsis mounted on a shaft 1a and is connected by gears, not shown, to anoffset roller which is turnable about a stationary shaft 10a and carriesa blanket 12. An inking device 4 to 2, as described with reference toFIG. 1, inks the printing form with magnetic ink so that during rotationof rollers 1 and 10, a mirror image of the text of the printing form istransferred to blanket 12. A support table and an electromagnet 32 in aslot of the same, form a supporting surface along which a copy sheet istransported by pairs of transporting rollers 26, 27 and 28, 29' from atable 124 to a box 31.

The copy sheets are manually placed on table 24 held against a movablestop member 125 which is mounted for pivotal movement and has a camfollower portion 125a cooperating with a cam-126 on roller 10 so thatwhen the text on blanket 12 is so positioned that a new copy sheet hasto be fed, stop member 125 is pivoted against the action of a spring toa position permitting manual shifting of copy sheet 102 into the bightbetween transporting rollers 26, 27 which further transport the copysheet into the gap between the core of electromagnet 32 and blanket 12.

The construction of electromagnets 32 and 35 is as described withreference to FIGS. 1 and 2. The cores of electromagnets 32 and 35 may besubdivided in axial direction corresponding to the columnsof the text,but for the sake of simplicity it may be assumed that the cores ofelectromagnets 32 and 35 have anarrow elongated shape corresponding to aline section of the printing form and of the transferred image onblanket 12.

Pulley and belt means 14' connect printing roller 1 with a rotarycontact arm 16 so that the same turns in synchronism'with rollers 1 and10 and successively passes over a plurality of stationary contacts 17whose number and positions correspond to the number and positions of theline sections of the printing form, only three stationary contacts 17a,17b, 170 being shown for the sake of simplicity. Contacts 17a, 17b, 170are respectively connected by selector-switches 20a, 20b, 200 to themain line 21 which, together with main line 22, is connected to 9.voltage sourcefSelector keys T, of which only selector keys T1, T2, T3are shown for the sake of simplicity, can be operated to selectively andindividually close selector switches '20.

The arrangement is such that when contact arm 16 engages a stationarycontact 17, the transferred image of a corresponding line section of theprinting form is located in the narrow gap between blanket 12 and theend face of the core of electromagnet 32.

Contact arm 16 is also connected to a lever arm 118 pivotally mounted ona journal 117 and normally urged by a spring 119 toa position abutting astop 120. A contact 122 on lever arm 118 cooperates with a stationarycontact 121 which is connected to one end of the winding of anelectromagnetic means 127, and to one end of the winding ofelectromagnet 32.

Contact arm 16 is also connected to one end of the winding of anelectromagnetic means 115. The second ends of electromagnetic means 127,32, and 115 are all connected to the second main line 22.

Consequently, electromagnetic means 115 will be energized when contactarm 16 engages any one of stationary contacts 17 whose correlatedselector switch 24 is closed.

On the other hand, electromagnetic means 127 and 32 will also requireclosing of contacts 121, 122 for ener gization.

Drive means 52 include a friction wheel 52: which cooperates with afriction wheel 56 mounted on a lever 58. and connected by pulley andbelt means 55 with roller 10 so that the same is rotated in the positionof FIG. 7 and drives through gears, not shown, printing roller 1 fromwhich the rotation of contact arm 16 is derived.

A spring 62 urges lever 58 to the position in which the rotary elementsrotate. A control lever 110 has an engaging portion cooperating withportion 169 of lever 58 while abutting a stop 114 under the action of aspring 113. Lever 110 is articulated to the armature of electromagneticmeans 127 by a lost motion connection.

Electromagnetic means 115 has an armature connected to a. lever which ismounted on a stationary pivot 111 and articulated to lever 114 Lever 118which carries contact 122 has a brake block 116 adapted to cooperatewith friction wheel 56. In the normal position illustrated in FIG. 7,friction wheel 56 is spaced from brake block 116 and rotated by drivewheel 52a.

An adjusting screw 123 in a stationary frame part can be used foradjusting the exact distance between contacts 121 and 122 since contact121 is mounted on a resilient arm.

When a printing operation is to be started, the operator selects desiredline sections of the printing form for printing. All other line sectionsare omitted. The selection is carried out by depressing selected keys T,each key being associated, for example by indica, with a line section ofthe printing form. For example, key T1 may be associated with the headsection of the printing form, key T2 with the first line, key T3 withthe second line, and so forth. It may be assumed that keys T1 and T2 aredepressed, and key T3 is left open.

When drive means 52 of the machine are started, for example by.switching on a motor, not shown, friction Wheel rotates and transmission55 transmits the rotation to roller 10 which drives printing roller 1through a transmission, not shown, so that contact arm 16 is rotated bytransmission 14', The printing form is inked by inking roller 4, and thetext thereon transferred to blanket 12. When the portion of blanket 12carrying the transferred image of the head section of the printing formapproaches the gap between the blanket and electromagnetic means 32,contact arm 16 approaches contact 17a. When contact arm 16 engagescontact 17a, electromagnetic means 115 is connected to the voltagesource 21, 22 since selector switch 20a is closed. The armature ofelectromagnetic means 115 turns lever 112 and moves control leverdownward as viewed in FIG. 7 which is possible due to a pin and slotconnection between control lever 110 and the armature of electromagneticmeans 127.

The transverse projection of control lever 11%) moves engaging portion101 of lever 58 downward so that friction wheel 56 is separated fromdrive friction wheel 52a and moved into engagement with brake block 116whereupon lever 58 is further moved while turning about shaft 10a untillever 118 has been turned againset the action of spring 119 to aposition in which contact 122 engages contact 121. I 1

At the moment of engagement between friction wheel 56 and brake block116, rotary members 10, 1 and 16 are braked, and the position of contact121 was adjusted by adjusting screw 123 so that the rotary elements stopwhen contacts 122, 121 engage each other and close the circuit ofelectromagnetic means 32 and 35, the winding of electromagnetic means 35being connected in parallel with the winding of electromagnetic means 32as described with reference to FIG. 2.

At this moment, roller 10 is stopped with the portion of blanket 12carrying the desired head section of the text located directly oppositethe axially elongated narrow end face of the core of electromagneticmeans 32, and between the same and the correspondingly shaped end faceof the core of electromagnetic means 35.

Since the circuit of electromagnetic means 32, 35 is closed by contacts121, 122, a magnetic field is produced in the gap permeating the blanketand the wall of roller 10, and magnetically attracting the magneticprinting ink so that the same is transferred from the blanket to the'copy sheet covering the end face of the core of electromagnetic means32. Due to the narrow and elongated shape of the cores of theelectromagnetic means 32 and 35, only ink representing the text of therespective selected line section is transferred to the copy sheet. Sinceroller 10 is stopped, the outline of the section is preciselymaintained.

At the same time, electromagnetic means 127 was connected to the voltagesource by the closed contacts 121, 122 and the armature ofelectromagnetic means 127 turns lever 110 from the position holdingfriction wheel -6 on the surface of the brake block 116 in clockwisedirection to a position in which the transverse projection of controllever 110 releases engaging portion 109 of lever 58 so that spring 62turns lever 58 back in counterclockwise direction. Friction wheel 56 isfirst disengaged from brake block 116 so that spring 119 returns leverarm 118 to the position abutting stop 120 in which contacts 121, 122 areseparated causing de-energization of electromagnetic means 32, 35 and127 so that spring 113 can return control lever 110 to the normalillustrated position. Thereupon friction wheel 56 moves further underthe action of spring 62 into engagement with drive 'wheel 52a.

Rotation of the rotary members is again started, and since transportingrollers 26, 27 are also connected by transmission means, not shown, withroller 10, the copy sheet is transported to a position in which itsfirst line section is located in the gap. At this moment, contact arm 16engages stationary contact 17b so that the circuit of electromagneticmeans 115 is completed through the closed selector switch 20b. Theoperations described with reference to the head section of the text arerepeated, and the first line of the text is printed adjacent the headsection while roller 19 is at a standstill. Thereupon the rotary partstart again to turn after engagement between friction wheel 56 and drivefriction wheel 52a and since contact 170 is not connected to the voltagesource 21 since selector switch 20c is open, roller is not stopped, andthe inked image of the second line of the text passes electromagneticmeans 32, 35 without being printed.

From the above descriptions of several embodiments of the invention, itwill become apparent that in all embodiments of the invention, twosurfaces forming a gap :move at the same speed, including zero speedcorrespond .ing to standstill of the surfaces while magnetic ink istransferred from one surface to the other surface by a magnetic field.Selector means, preferably including selector keys and selector switchesassociated with sections of the printing form, which may be linesections or column sections, cause energization of the electromagneticmeans producing the magnetic field whenever a desired section of thetext passes the printing line where the electromagnetic means producingthe magnetic field is located. The selec- .tion may also be carried outby magnetically compensating a constant magnetic field which transfersink from one surface to the other surface except when compensated atselected points by a selectively produced opposing magnetic field.

It will be understood that each of the elements de scribed above, or twoor more together, may also find a useful application in other types ofprinting machines differing from the types described above.

While theinvention has been illustrated and described as embodied in amethod and apparatus for selective printing in which magnetic istransferred by a magnetic field to produce imprints only of selectedsections of the printing form on a copy sheet, it is not intended to belimited to the details shown, since various modifications and structuralchanges may be made without departing in any way from the spirit of thepresent invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to'becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A selective printing machine comprising, in combination, a set ofelectroma-gnets disposed in a row for producing, when energized, narrowmagnetic field sections having in a direction transverse to said row thesame narrow predetermined width corresponding to the Width of a line,and having in the direction of said row a length corresponding to thewidth of a column of a text to be printed; first means having a firstsurface; second means having a second surface forming a gap with saidfirst surface; means for applying a 'magnetizable ink to said firstsurface so that said ink forms text sections having said predeterminedwidth on corresponding surface sections; drive means for driving saidfirst and second means for moving said surfaces in said transversedirection in synchronism through said magnetic field; means forenergizing selected electromagnets only when selected sections of saidsurfaces pass through said magnetic field so that the same control thetransfer of ink from a section of said first surface having a lengthcorresponding to the length of at least one magnetic field section andsaid predeter-. mined width, to a corresponding section of said secondsurface whereby only text sections selected by energization of .saidelectromagnetics and having said predetermined Width corresponding to aline, and a length corresponding to the width of a column aretransferred; and electric circuit means for connecting saidelectromagnets with a voltage source, and including a set of first andsecond cooperating contact means of which said first contact means isdriven in synchronisrn with said first and second means and With saidsurface, each second contact means including a plurality of stationarycontacts connected with each said electromagnet, respectively; and a setof pluralities of selector switches respectively correlated with linesections, said sets of pluralities of selector switches beingrespectively connected with said sets of first and second contact means,said selector switches of each set being respectively connected withsaid stationary contacts and selectively operable for causingenergization of selected electromagnets only when line sections selectedby operation of selected selector switches pass through magnetic fieldsections selected by operation of selector switches so that saidelectromagnets transfer ink from at least one selected line and columnarea of said first surface to a corresponding area of said secondsurface.

2. A printing machine as set forth in claim 1 including a printingroller for carrying a printing form; and wherein said first meansinclude an offset roller and a blanket on the same cooperating with saidprinting form and having said first surface; and wherein said secondmeans include transporting means and supporting means for a copy sheethaving said second surface.

3. A printing machine as set forth in claim 1 including a printingroller for carrying a printing form; and wherein said first meansinclude an offset roller and a blanket on the same cooperating with saidprinting form and having said first surface; and wherein said secondmeans includes a roller carrying said electromagnetic means andincluding means for gripping and transporting a copy sheet having saidsecond surface.

4. A selective printing machine comprising, in combination,electromagnetic means for producing, when energized, a magnetic fieldhaving in a given direction a predetermined Width corresponding to asection of text to be printed; first means including a roller having afirst surface; second means having a second surface forming a gap with,said first surface; means for applying a magnetizable ink to said firstsurface so that said ink forms text sections having said predeterminedwidth on corresponding surface sections; drive means for driving saidfirst and second means for moving said surfaces in said given directionin synchronism through said magnetic field; means for energizing saidelectromagnetic means only when selected text sections pass through saidmagnetic field, and for deenergizing said electromagnetic means whennon-selected text sections pass the same so that the same controls thetransfer of ink of each selected text section on a section of said firstsurface having said predetermined width to a corresponding section ofsaid second surface whereby only text sections selected by,

energization of said electromagnetic means and having said predeterminedwidth are transferred; said electromagnetic means comprising a firstelectromagnetic means including a first core having an end face formingsaid gap with said first surface of said roller and being narrow in saidgiven direction, and a second electromagnetic means located in saidroller and having a second core with an end face narrow in said givendirection and confronting said end face of said first core, said firstand second electromagnetic means being stationary so that said first andsecond surfaces move between said end faces.

5. A selective printing machine as set forth in claim 4 wherein saidfirst and second cores each comprise a plurality of core sections, andincluding a winding around each of said core sections, and means forselectively en ergizing the winding of pairs of core sections of saidfirst and second cores.

6. A selective printing machine comprising, in combination,electromagnetic means for producing, when energized, a magnetic fieldhaving in a given direction a predetermined 'wid th corresponding to asection of text to be printed; first means having a first surface;second means having a second surface forming a gap with. said firstsurface; means for applying a magnetizable ink to said first surface sothat said ink forms text sections having said predetermined width oncorresponding surface sections; drive means for driving said first andsecond means for moving said surfaces in said .givendirection insynchronism through said magnetic field; means for energizing saidelectromagnetic means only when selected text sections pass through saidmagnetic field, and for deenergizing said electromagnetic means whennonselected text sections pass the same so that the same controls thetransfer of ink of each selected text section on a section of said firstsurface having said predetermined width to a corresponding section ofsaid second surface whereby only text sections selected by energizationof said electromagnetic means and having'said predeter mined width aretransferred; said electromagnetic means comprising a horse shoe magnethaving closely spaced north pole and south pole end portions forming inthe region of said gap a narrow magnetic field passing through saidsurfaces.

7. A selective printing machine comprising, in combination,electromagnetic means for producing, when energized, a magnetic fieldhaving in a given direction a predetermined width corresponding to asection of text to be printed; first means having a first surface;second means having a second surface forming a gap with said firstsurface; means for applying a magnetizable ink to said first surface sothat said ink forms text sections having said predetermined width oncorresponding surface sections; drive means for driving said first andsecond means for moving said surfaces in said given direction insynchronism through said magnetic field; means for energizing saidelectromagnetic means only when selected text sections pass through saidmagnetic field, and for deenergizing said electromagnetic means whennonselected text sections pass the same so that the same controls thetransfer of ink of each selected text section on a section of said firstsurface having said predetermined width to a corresponding section ofsaid second surface whereby only text sections selected by energizationof said electromagnetic means and having said predetermined width aretransferred and comprising means for stopping movement of said firstmeans; and control means controlling said stopping means and said meansfor energizing said electromagnetic means so that said first surface isat a standstill when said electromagnetic means are energized and ink istransferred from said first surface to said second surface.

8. A selective printing machine comprising, in combination,electromagnetic means for producing, when energized, a magnetic fieldhaving in a given direction a predetermined width corresponding to asection of text to be printed; first means including a roller having afirst surface; second means having a second surface forming a gap withsaid first surface; means for applying a magnetiza ble ink to said firstsurface so that said ink forms text sections having said predeterminedwidth on corresponding surface sections; drive means for driving saidfirst and second means for moving said surfaces in said given directionin synchronism through said magnetic field; means for energizing saidelectromagnetic means only when selected text sections pass through saidmagnetic field, and for deenergizing said electromagnetic means whennon-selected text sections pass the same so that the same controls thetransfer of ink of each selected text section on a section of said firstsurface having said predetermined width to a corresponding section ofsaid second surface whereby only text sections selected by energizationof said electromagnetic means and having said predetermined width aretransferred; wherein said second means is a copy sheet; comprisingtransporting means for said copy sheet; wherein said drive means includea drive shaft and a coupling between said drive shaft and said roller,spring means for holding said coupling in an engaged position,transmission means con necting said roller with said transporting means;means for braking said roller in the disengaged position of saidcoupling; means for shifting said coupling from said engaged position tosaid disengaged position when a selected section of the text on saidfirst surface passes through said magnetic field so that the roller andsaid first surface are braked and stopped during the transfer of inkfrom said first surface to said second surface; and switch means in thecircuit of said electromagnetic means closed in said disengaged positionof said coupling for energizing said electromagnetic means only whensaid roller is stopped.

9. A selective printing machine comprising, in combination, a rollerhaving a first peripheral surface; means for applying a magnetic ink tosaid first surface in the form of an inked mirror image of a text havingsections; drive means including a rotary friction wheel; a controlswitch having a movable arm; a brake block on said movable arm; a springurging said movable arm and said brake block to a normal position ofrest in which said control switch is open; a movable coupling memberhaving a rotary friction wheel located between said drive wheel and saidbrake block, and being shiftable between a position in which saidfriction wheel is driven, and a position in which said friction wheel isbraked and stopped by said brake block; transmission means connectingsaid friction wheel with said roller for rotating the latter;transporting means for transporting a copy sheet having a second surfacein a given direction along a path so that said first and second surfacesform a gap; means connecting said transporting means with said rollerfor synchronous rotation so that said first and second surfaces move insynchronism; electromagnetic means located along said gap and havingcore means narrow in said direction for producing, when energized, amagnetic field having in said direction a predetermined widthcorresponding to a section of the text; first and second cooperatingcontact means of which one contact means is driven from said roller insynchronism with the same, said first contact means including a contactarm, and said second contact means including a plurality of contactssuccessively engaged by said contact arm during rotation of said onecontact means; a plurality of selector switches respectively connectedwith said contacts; a contact on said movable arm of said control switchbeing connected with said contact arm, and another contact of saidcontrol switch being connected with said electromagnetic means; a firstcontrol magnet connected with said control arm to be energized inpositions of said first and second contact means determined by selectedclosed selector switches, said first control magnet being operativelyconnected with said member carrying said friction wheel for moving thelatter into engagement with said brake block whereby said movable arm ofsaid control switch is displaced and the contacts of the control switchengage each other whereby said electromagnetic means is energized; and asecond control magnet in the circuit of said control switch andoperatively connected with said member carrying said friction wheel forreturning the latter to the position driven by said drive means wherebyink is transferred from said first surface to the second surface whilesaid roller and said copy sheet are at a standstill.

'10. A selective printing machine as set forth in claim 9 and includingmeans for adjusting the distance between said contacts of said controlswitch.

11. A selective printing machine as set forth in claim 9 wherein each ofsaid selector switches is associated with one of said sections of saidtext; and including a plurality of manually operated keys respectivelyconnected with said selector switches whereby the latter are closed byselective operation of said selector keys.

12. A selective printing machine as set forth in claim 9 wherein saidelectromagnetic means includes a winding connected with said controlswitch, and a core having a narrow elongated end face having a widthcorresponding to the Width of a section of said text, and a lengthcorresponding to the length of the text section.

13. A selective printing machine as set forth in claim 9 wherein saidelectromagnetic means includes a first electromagnetic means having afirst core located opposite said first surface of said roller so thatsaid copy sheet is located between said first code and said firstsurface of said roller, and second electromagnetic means located withinsaid roller and including a second core located opposite said first coreand having a polarity opposite to the polarity of said first core sothat the magnetic field is produced between said first and second cores.

14. A selective printing machine comprising, in combination, a rotaryprinting roller having a peripheral surface; an elastic magnetizableprinting form having a first surface with a text having text sectionsmounted on said peripheral surface; inking means for inking said firstsurface of said printing form; a roller having a second surface forminga gap with said first surface; means for rotating said rollers insynchronism so that said surfaces move in synchronism in a givendirection; electromagnetic means located in at least one of said rollersand being energizable for producing in said gap a magnetic field narrowin said given direction corresponding to the circumferential extensionof a text section on said printing form; means for energizing saidelectromagnetic means only when selected sections of said printing formpass through said gap, and for deenergizing said electromagnetic meanswhen non-selected text sections pass the same so that the magnetic fielddeforms a section of said printing form into a buldge in contact withsaid second surface for transferring the ink of one text section from asection of said first surface of said printing form to a correspondingsection of said second surface of said blanket whereby images of onlyselected sections are transferred.

15. A selective printing machine as set forth in claim 8 and including arotary magnetic cleaning roll cooperating with one of said surfaces andbeing spaced from the same by a gap, said rotary magnetic roll beingpositioned so that the inked text sections on said one surface ar riveat said magnetic cleaning roll after having engaged a copy sheet, saidmagnetic cleaning roll producing a magnetic force attracting magneticink on said one surface so that the latter is cleaned, and means forremoving ink from said magnetic cleaning roll.

16. In a selective printing machine, in combination, a printing rollerhaving a peripheral surface for carrying a magnetic printing formpermanently magnetized in accordance with a text having text sections;an inking roller having a peripheral surface forming a gap with thesurface of the printing form; means for applying a magnetic ink to saidperipheral surface of said inking roller; means for rotating saidprinting roller and said inking roller in synchronism; said inkingroller having a plurality of circumferentially adjacent magnetizablesections narrow in circumferential direction corresponding to thecircumferential extension of a text section on said printing form, and awinding about each of said magnetizable sections; commutator meansconnected with said inking roller for rotation and havingcircumferentially adjacent contacts respectively electrically connectedwith said windings; slide contact means cooperating with said commutatorcontacts; and selector means for energizing selected windings whenselected text sections of said printing form are located at said gapwhereby ink is transferred from said peripheral surface to said surfaceof Said printing form by the magnetic force exerted by said magneticprinting form when a winding passing said gap is not energized, whereaswhen an energized winding is located at said gap, the magnetic force ofsaid magnetic printing form is compensated so that no ink is transferredfrom said inking roller to the respective text section of said printingform.

17. Inking apparatus as set forth in claim 16 and including moisteningmeans for moistening said surface of said printing form.

18. Inking apparatus as set forth in claim 16 wherein said means forenergizing said windings include contact means rotating in synchronismwith said inking roller; and a plurality of selector switches connectedby said contact means with said windings so that only selected windingsare energized when located at said gap.

19. A selective printing apparatus comprising, in combination, a firstroller having a first surface; means for applying ink to said firstsurface in the form of atext having sections adjacent in circumferentialdirection of said first roller; a second roller including a plurality ofmagnetizable circurnferentially adjacent core sections, and a windingabout each of said core sections, said second roller having grippermeans for gripping and transporting copy sheets having a second surfaceso that said first and second surfaces for a gap, said windings andcores, when energized, producing a magnetic field in said gap having apredetermined width in circumferential direction of said first andsecond roller corresponding to a section of the text inked on said firstsurface; drive means; first transmission means including a couplinghaving a coupled position for connecting said drive means with saidfirst roller and a disengaged position; second transmission meansincluding a second coupling having a coupled position for connectingsaid second roller with said drive means and a disengaged position;brake means for braking said first and second coupling means and therebysaid first and second rollers in said disengaged positions; a firstspring urging said first coupling means to said coupling position; asecond spring urging said second coupling means to said disengagedposition; a first control magnet connected with said first couplingmeans for moving the same to said disengaged position against the actionof said first spring; a second control magnet connected to the secondcoupling means for moving the same to said coupling position; a rotarycontrol contact means driven in synchronism with said first and secondrollers; a plurality of selector switches respectively associated withsaid text sections and electrically connected with said rotary contactmeans, said selector switches being respectively connected with saidwindings of said second roller so that selected windings are energizedwhen the respective core section is located at said gap and therespective selector switch is closed; manually operable means fornormally blocking said first coupling means in said disengaged positionin which said first roller is blocked so that upon manual operation ofsaid blocking means said first coupling means is released to be moved bysaid first spring to said coupled position whereby said first roller isdriven; and circuit means connecting said rotary contact means with saidsecond control magnet and including a control switch which is normallyclosed so that said second control magnet is energized and moves saidsecond coupling means to said coupled position whereby said secondroller rotates in synchronism with said first roller while a selectedwinding is energized, said second control magnet being deenergized whensaid rotary contact means connects an open selector switch into thecircuit so that second spring moves said second coupling means to saiddisengaged position whereby said second roller is braked and stoppedwhile an undesired section of the text moves with the rotating firstroller through said gap; and a cam rotating with said second roller andcooperating with said control switch for shifting the same to an openposition whereby said first control magnet moves said first couplingmeans to said disengaged position, and said second spring moves saidsecond coupling means to said disengaged position so that said first andsecond rollers are braked and stopped.

20. A selective printing machine as set forth in claim 19 wherein saidfirst and second coupling means respectively include first and secondcoupling levers and first and second friction Wheels rotatably mountedon said first and second coupling levers; wherein said drive meansinclude a friction drive wheel; and wherein said first and secondfriction wheels engage said drive wheel when said first and secondcoupling means are in said coupled position, and engage said brakemembers when said first and second coupling means are in said disengagedpositions; and wherein said first and second control magnets and saidfirst and second springs are respectively connected with said first andsecond coupling levers.

21. A selective printing machine as set forth in claim 19 and includinga commutator rotating in synchronism with said second roller and havingcommutator contacts connected With said windings; and including slidecontact means engaging said commutator contacts and electricallyconnected with said selector switches.

22. A selective printing machine as set forth in claim 19 and includinga plurality of stationary contacts respectively associated with textsections and respectively connected with said selector switches, saidstationary contacts being successively engaged by said rotary contactmeans; and including a pair of stationary contacts respectivelyconnected to the contacts of said control switch, and being closed bysaid rotary contact arm after each revolution of said first roller.

23. A selective printing machine comprising, in combination,electromagnetic means for producing, when energized, a magnetic fieldhaving in a given direction a predetermined Width corresponding to asection of a text to be printed; first means having a first surface;second means having a second surface forming a gap with said firstsurface; means for applying a magnetic ink to said first surface so thatsaid ink forms text sections having said predetermined width oncorresponding surface sections; drive means; first and second couplingmeans for connecting the drive means with said first and second means,respectively, and having a coupled position for moving said surfaces insaid given direction through said magnetic field, and a disengagedposition; brake means controlled by said coupling means in saiddisengaged position for braking and stopping said first and second meanswith said first and second surfaces; selector means for energizing saidelectromagnetic means only when selected sections pass through saidmagnetic field, and for deenergizing said electromagnetic means whennon-selected text sections pass the same so that the same controls thetransfer of magnetic ink of each selected test section on a section ofsaid first surface having said predetermined width to a correspondingsection of said second surface whereby only text sections selected byenergization of the electromagnetic means and having said predeterminedwidth are printed; and means controlled by said selector means andcontrolling said first and second coupling means so that the same aremoved to said disengaged positions and said first and second means arebraked and stopped while said electromagnetic means is energized and inkis transferred from said first surface to said second surface.

24. A selective printing machine comprising, in combination, anelectromagnetic means for producing, when energized, a magnetic fieldhaving in a given direction a predetermined Width corresponding to asection of a text; first means having a first surface; second meanshaving a second surface forming a gap with said first surface; means forapplying a magnetic ink to said first surface so that said ink formstext sections having said predetermined width on corresponding surfacesections; drive means for driving said first means for moving said firstsurface in a given direction through said magnetic field; coupling meansconnecting said drive means with said second means for moving saidsecond surface in synchronism with said first surface through saidmagnetic field; selector means for energizing said electromagnetic meansonly with selected text sections pass through said magnetic field, andfor deenergizing said electromagnetic means when non-selected textsections pass the same so that the same controls the transfer ofmagnetic ink of each selected text section on a section of said firstsurface having said predetermined width to a corresponding section ofsaid second surface whereby only text sections selected by energizationof the electromagnetic means and having said predetermined width aretransferred; and means controlled by said selector means for moving saidcoupling means to a disengaged position, and for braking and stoppingsaid second means when non-selected sections of said first surface passsaid electromagnetic means in de-energized condition whereby transferredimprints of text sections spaced on said first surface are made adjacenteach other on said second surface.

References Cited UNITED STATES PATENTS (Other references on followingpage) 23 UNITED STATES PATENTS Huebner 101181 Huebner 101-426 Huebner101--426 Wellcome 101-149.2 Sims 17823 Sims 1786.6

Berry 101401.1

24 Kuleska 117-17.5 Ritzerfeld et a1. 101132.5 Ritzerfeld et a1 101--91Ritzerfeld et a1 101--142 Berry 101-426 Schwartz 10192 WILLIAM B. PENN,Primary Examiner.

